More than two centuries later, perils of another kind still lurk just outside the national park's boundaries.

On a trip east along the park's Outer Line Drive, replicas of the wooden huts that members of Muhlenberg's brigade built in December 1777 come into view on the right. Barely visible a mile away across the park's "Grand Parade" is the steeple of Washington Memorial Chapel. The bucolic space is ringed by tree-covered hills.

On the left, however, the 21st century pushes in. Multistory hotels, offices, restaurants, stores and the Pennsylvania Turnpike all have sprung up within cannon-range of the park's border.

Valley Forge is just 20 miles from downtown Philadelphia in a fast-growing portion of adjacentMontgomery County. Recent experience with development near the national park goes a long way toward explaining why plans for a museum and conference center have raised the ire of some neighbors and conservation organizations.

Supporters, however, say that the proposed site -- secluded farm fields across the Schuylkill River from the main portion of the national park -- is an excellent location for what will become the nation's only museum devoted to the birth of American independence.

The American Revolution Center and its predecessor, the Valley Forge Historical Society, began efforts in 1995. The initial plan called for the center, a nonprofit corporation with a collection of more than 15,000 Colonial-era objects, to construct a 130,000-square-foot museum on Valley Forge land owned by the National Park Service. The new museum would have been constructed near the existing visitors center and parking lots.

Those plans stalled in 2004, when the center and the park service couldn't agree on the size and control of the facility.

Then earlier this year, the center announced plans to buy 78 acres in Montgomery County from the Catholic Archdiocese of Philadelphia. That privately owned tract is north of the Schuylkill River, separating it from the main portion of Valley Forge. The land, however, is within the "Congressionally authorized boundaries" of the park.

The sale went through in September after Lower Providence Township approved a revised zoning ordinance that paves the way for construction of the museum, a small hotel and a conference center.

Supporters say the facility is badly needed.

"No other museum does this: tells why the American Revolution happened, what happened and what came out of it," said ZeeAnn Mason, the center's senior vice president.

The conference center and 99-room hotel are critical elements for the success of the project, Ms. Mason said.

"This is an expensive area," she said. "The hotel will provide accommodations for interns and students working here. The conference center -- and it's not a convention center -- will assure a location for international meetings and symposiums on historical topics."

Cinda M. Waldbuesser, state program manager for the National Parks Conservation Association, agrees with the need for a museum. Her nonprofit lobbying and advocacy group, however, rejects the location.

"We've never opposed the idea of building a museum to tell the story of the American Revolution," she said. "We believe it would be a win-win situation in the originally proposed location -- near the park's current visitors center."

That site is an under-used parking area, she said, that is served with existing utilities. The land also is disturbed ground, meaning that construction there would not endanger potential archeological sites. It also is near the center of the park.

The proposed tract likely includes the site of the camp's commissary -- a slaughterhouse, animal pens and buildings where butchers could salt and store meat. It also was the staging ground from which the troops marched out of Valley Forge at the end of the encampment in June 1778.

"The army actually built a bridge across the river near there -- the only temporary bridge built during the American Revolution," Ms. Waldbuesser said.

The conservation association is not alone in its opposition. Some local residents and the Sierra Club also oppose the American Revolution Center's plans.

Federal purchase of the site would be the ideal solution, Ms. Waldbuesser said. "Valley Forge is a national icon and deserves to be protected for future generations to enjoy."

That isn't going to happen, Ms. Mason said, and the center's proposal offers the best chance for preserving most of the site. That is because the National Park Service must struggle to maintain the land and buildings it already owns at Valley Forge, she said.

The center tract is by no means virgin land, she said. The sounds of traffic from busy Route 422, the Pottstown Expressway, are audible everywhere on the site. The land already is bisected by an underground gas line and 50-foot-tall electrical towers. It has been farmed for most of the past three centuries.

The initial reaction of Valley Forge Park Superintendent Mike Caldwell to the new center proposal, and to the zoning change necessary for it to be carried out, was strong opposition.

The Park Service, however, has not joined in the lawsuit seeking to overturn the zoning ordinance, and the park's assistant superintendent struck a more conciliatory tone during a recent phone interview.

"We are interested in working with ARC, no matter where the museum ends up," Barbara Pollarine said.

While it continues its $150 million fund-raising effort, the center has begun first steps of site preparation.

Archeologists from BRAVO, the Battlefield Restoration and Archaeological Organization, based in Freehold, N.J., have carried out "shovel tests." Last fall, teams dug 16 small holes per acre, then sifted through the soil in search of artifacts.

Those efforts turned up the kinds of items likely to be found in farm fields: mostly fence nails and broken-off bits of agricultural equipment, BRAVO President Dan Silivich said.

"This is the most sensitive and respectful dig I've ever known about," Mr. Silivich said.

On the Park Service map of Valley Forge, the site of the encampment-era bridge, known as Sullivan's Bridge, is about 200 yards from the edge of the center's property. The bulk of any commissary remains are likely to be found closer to the bridge site, which is Park Service land, Ms. Mason and Mr. Silivich said.

The center remains eager to cooperate with the National Park Service as it develops its site, Ms. Mason said. That cooperation would extend to helping with fund-raising for re-creation of Sullivan's Bridge, which would link the north and south portions of Valley Forge with the museum site.

The American Revolution Center traces its roots back to the preservation efforts of the Rev. Dr. W. Herbert Burk, a collector of Washington memorabilia, a founder of the Valley Forge Historical Society and the first rector of the Washington Memorial Chapel.

Within a few decades of its founding in 1903, the historical society was running out of room for its collection of Revolutionary War artifacts. According to organization minutes, officers first considered acquiring land north of the Schuylkill for a new museum in the 1930s.

"It was this very spot," Ms. Mason said during a recent visit to the site. "We feel we are channeling Dr. Burk with this project."